Depends on how close to stock you want. If you want a stock (H-pipe, stock mufflers, pipes out to back) exhaust, get an H-pipe from NPD and have the rest bent up by an exhust shop. Better performance can be had with an X-pipe, but that would have to be custom bent for the a 70/351.
I bought an H-pipe from NPD and had the rest built by local Midas. They used Raven mufflers which sound a little louder than stock, but have a non-stock black finish.